Quickest / easiest way to travel Saigon-Hanoi-Sapa-Halong Bay?

Yes, (sounds great ideal)  But, um, just a suggestion...

Go Ogle to do your own (objective) research.

I have found TripAdvisor.com and Booking.com to be the best in reviews of both guided and solo tours (anywhere!!)   Sa Pa is (very) popular, particularly now (check the weather to see why)   AND there are (literally) hundreds of reviews...

Bus and train can also be pre - booked.   ALL Ha Noi hotels & hostels advertise this popular tourist attraction and the homestay is preferred by the majority.

I prefer to fly solo, so read up on your own preferences.

As for a 'Leisurely' (???)  ..stay in Ha Noi..?    (you cannot be serious..?)   
 
    The origin of 'Tourist Trap' (probably) originated here.   Too much to see, do, feel.
And although I don't recommend queuing to see Viet Nam's famous figure, Ha Noi is cluttered (literally) with Museums, Lakes, the Old Quarter, History and rice fields close by stretching to infinity.   You can (easily) spend a month here and still not see all the major attractions. 

Forgive my mirth.   A Leisurely spent day and night..?      ..IN HA NOI..?     

I weep for your innocence.

   A harsh awakening awaits.             

Having seen this asked before on another forum, the answer came from several people that it's better to catch the bus than the train.

Thanks Bazza - we're well aware of Trip Advisor and its associated entity booking.com (level 6 and 'genius' contributor respectively) - and have lived, worked, married and retired in Vietnam since 1988, including the first 5 or 6 years in Hanoi, so well practised at "leisurely" pursuits by now (but thanks for the concern!).  What I was hoping for was some uptodate 'practical' info such as colinoscapee's "bus before train", although that stuff is just as subjective as anything on the various forums, of course. 
Anyway, thanks again to you both, but our uncle in Hanoi is on the case now (no, his name is not Ho!) - we wanted to make sure we could get through Hanoi to both Sapa and Halong Bay without too long a stay in the city on either leg, and he's sorted that already (with buses bothways, as it happens!).
Cheers - and here's to our trip, including a leisurely day and overnight stay in Hanoi catching up with family and old friends!

I found this exchange very interesting. Some people just don't get it.

Meaning?

..that I am suitably chastened!

My cryptic humour (obviously) needs work...     

Still, buses are only for brave people by me.   

So yes, Cheers and Bon Voyage Better...         

linhmartin wrote:

Meaning?

You had a rather simole question.  The first reply you get is full of sarcasm and doesn't address your primary concern. Your reply is informative, educational and kind.

Thanks GF, and it ain't always easy to avoid the temptation to get angry when you ask a genuine question and get a mouthful of self-serving crap in response, but I tell myself that such people can't help themselves and they're not important to my life anyway - so biting the lip hard is often but not always the best way to go (and I trust you didn't miss my own bit of sarcasm at the end...).